Leaded gasoline was invented by General Motors in the 1920s. Tetraethyl lead was a cheap octane booster and antiknock agent. It prevented exhaust valve and valve seat wear and allowed much higher engine compression. It also could have been the cause of the big post-war crime wave, researchers say.
Several researchers, cited in an article in Mother Jones, tied the rise of crime in the ‘60s and ‘70s to rising levels of lead in the atmosphere and in people. They also tied the drop in crime since the ‘90s to diminished lead exposure after leaded gasoline was phased out.
Lead exposure in small children has been linked to lower IQ, hyperactivity, behavioral problems, learning disabilities, and now – crime. Crime manifests itself decades after exposure: Toddlers who ingested high levels of lead in the ’40s and ’50s were seen more likely to become violent criminals in the ’60s, ’70s, and ’80s.
Interestingly, leaded gasoline could still cause mayhem if there would not have been another big city problem: Smog. Car emissions were battled with catalytic converters, but leaded gasoline was murder on the catalytic converters, which led to a phase-out of lead in gasoline.